Effects of gamma irradiation on the insulated-gate bipolar transistor

The effects of gamma irradiation on the International Rectifier IRGBC20 insulated-gate bipolar transistor (IGBT) was investigated. These devices were found to be sensitive to gamma irradiation due to their metal-oxide-semiconductor field-effect-transistor (MOSFET) input drive. Total doses as small as 50 Krads(Si) increased the saturated collector current (I_c) by an order of magnitude when the irradiation was performed with zero gate bias. For a constant (V_g − V_th) of 0.5 V, I_c decreased to about half its pre-irradiation value after irradiation to 40 Krads(Si). The threshold voltage of the MOSFET shifted in the negative direction with the largest and smallest shifts occurring for a positive and negative gate bias applied during the irradiation, respectively. The shift in threshold voltage saturated at the cut-in voltage of the P-i-N diode portion of the device, indicating that gamma irradiation does not affect the P-i-N diode. The reverse blocking leakage current of the device is not very sensitive to radiation below a total dose of 400 Krads(Si), but increases sharply for larger doses. All of these radiation-degraded characteristics of the IGBT are primarily the result of increasing interface-state and oxide-trapped charge densities with total radiation dose, which decreases the carrier channel mobility by increased carrier scattering. Both room temperature and 150°C annealing were observed to partially recover all of the device characteristics by reducing the radiation-induced oxide-trapped charges.     

Effect of gamma irradiation on the photoluminescence of porous silicon

The effect of gamma irradiation on the luminescence properties of porous silicon produced by the electrochemical technique is studied. Changes in the photoluminescence intensity between irradiation doses and over a period of several days after the last irradiation are recorded. The quenching of photoluminescence at low irradiation doses and recovery after further irradiation are registered. It is found that porous silicon is strongly oxidized after gamma irradiation and the oxidation process continues for several days after irradiation. It is conceived that the change in the photoluminescence spectra and intensity of porous silicon after gamma irradiation is caused by a change in the passivation type of the porous surface: instead of hydrogen passivation, more stable oxygen passivation is observed. To stabilize the photoluminescence spectra of porous silicon, the use of fullerenes is proposed. No considerable changes in the photoluminescence spectra during irradiation and up to 18 days after irradiation are detected in a porous silicon sample with a thermally deposited fullerene layer. It is shown that porous silicon samples with a deposited C₆₀ layer are stable to gamma irradiation and oxidation.     

人卵巢粘液性肿瘤来源的再确认

本文研究人卵巢粘液性肿瘤上皮细胞的超微结构特征,试图从形态学角度再确认其起源。取人卵巢粘液性肿瘤组织6例(良性3例,交界性1例,恶性2例)。经2．5％戊二醛及锇酸先后固定后,按常规电镜样品制做程序处理,电镜观察。     

人卵巢粘液性肿瘤来源的再确认

为研究人卵巢粘液性肿瘤上皮细胞的超微结构特征，试图从形态学角度再确认其起源。取人卵巢粘液性肿瘤组织6例及育龄妇女正常宫颈内膜组织3例。按常规透射电镜标本制作方法处理，并用Philips Tecnai10型电镜观察。卵巢粘液性肿瘤上皮为柱状上皮，多数细胞上核区的粘液分泌颗粒丰富。细胞游离面部分微绒毛的微丝形成中心根并深入胞质。上皮表面及微绒毛间可见糖萼，偶见纤毛细胞。少数细胞的形态则类似宫颈管的粘液细胞。结论：虽然卵巢粘液性肿瘤细胞的杯状细胞及微绒毛的中心根与肠上皮细胞的相似，但由于胃、肠上皮并无纤毛细胞，卵巢粘液性肿瘤纤毛细胞及类似宫颈管粘液细胞的出现，提示卵巢粘液性肿瘤是卵巢生发上皮向Miiller氏管化生后，逐渐向胃、肠细胞分化的结果。     

低剂量CO_2激光对茄子种子活力影响的研究

低剂量激光照射种子对其发芽率、发芽势、酶活性均有一定的刺激效应。郝丽珍等曾在青椒上作过研究。本文在茄子上也得到了类似的结果,进而为蔬菜种子播前处理提供了依据。 1 材料和方法 茄子品种为七叶X紫茄,含水量为8.33％,试验均选用饱满的大小均一的中等种子。将种子置于自制的种盘内照射,CO_2激光扩束后功率为4.05W,光斑直径为2.5cm,照射距离为     

绿色激光血管内照射最佳剂量的实验研究和临床应用

本文作者在研究了半导体绿色激光血管内照射安全阈值的基础上,进一步用实验的方法研究了在安全阈值内半导体绿色激光血管内照射的最佳剂量,找到了临床应用的依据。用波长为532nm的半导体绿色激光对犬进行血管内照射后,当每疗程总剂量在64．31J／nm^2-192.9J/mm^2时,将不同程度地改善血液流变学的主要指标,增强LDH和ANAE活性,提高SOD水平,降低LPO水平,增加红细胞计数等,与相同剂量的He-Ne激光（对照组）相比,某些指标优于红光。所以认为：绿色激光对犬血管内照射的最佳参量为：功率0．5－1．5mW,功率密度5．36mW/mm^2-1.79mW/mm^2,每疗程10次量为192.91J/mm^2-64.43J/mm^2。对30例银屑病和25例高血脂患者临床应用证明,其有效率达93％以上,实验证明：低强度绿色激光可以用于血管内照射治疗,但照射剂量要严格控制。     

Dependence of GaAs:Si persistent photoconductivity on temperature and α-particle irradiation

We investigated the photoconductivity of GaAs:Si epilayer on SI-GaAs specimens. We measured the current from the time we switched on the illumination and after switching it off as a function of time at various temperatures from 250 to 330 K. A small persistent photoconductivity starts to appear from 250 K. At 330 K a clear positive persistent photoconductivity (PPPC) appears. The persistent photoconductivity increases with temperature.Then the specimens were irradiated with α-particles from an Am²⁴¹ source at 330 K.A change in persistent photoconductivity is observed from the dose of 6×10¹² particles/cm². At higher doses not only the current increases, but also the PPC duration. We try to explain these phenomena on the base of the existing theoretical models.     

红外线照射对大鼠血脂和小鼠血糖水平的影响

为了研究红外线照射对高血脂和高血糖的作用机制,采用建立高血脂和高血糖模型的方法,对红外线照射治疗后大鼠血脂水平、小鼠血糖水平和血清超氧化物歧化酶活力、丙二醛浓度等指标进行了对比分析。结果表明,红外线照射能降低总胆固醇浓度(P0.01),能降低血糖浓度并恢复到正常水平(P0.05),对高血脂大鼠和高血糖小鼠的自由基有一定影响,具有增强超氧化物歧化酶活力、降低丙二醛浓度的作用,但对正常小鼠自由基未产生明显影响。这表明红外线照射治疗对高血脂和高血糖等疾病有良好的治疗效果和预防作用。     

The role of the system of proteolytic enzymes and their inhibitors in the pathogenesis of ovarian tumors in Wistar rats and the possibilities for correcting the disorders detected]

The system of proteolytic enzymes and their inhibitors was studied in tissues of ovarian tumours of Wistar rats. It has been revealed that activation of proteolysis enzymes is observed in the genesis of tumour growth against a background of the absence of protease inhibitors. The correction of revealed disturbances by introducing the inhibitors of proteolytic enzymes and hormone preparations has shown that contrical and norcolute are the most effective. The results obtained suggest the further search of preparation normalizing the condition of the given system.     

Effect of the level of "tar" in tobacco smoke on the risk of the occurrence of malignant tumors

Carcinogenic effect exerted by smoking on people depends on the chemical composition of tobacco smoke. It has been shown that relative risk of lung cancer, as well as its incidence and mortality are closely related to "tar" yield. Cigarettes produced in the USSR contain still high levels of "tar" and nicotine. A decrease of "tar" levels in the Soviet cigarettes may cause in 15-20 years a substantial reduction of lung cancer incidence and mortality in young and middle-aged people.     

激光穴位照射对大鼠束旁核单位伤害性反应的影响

48个束旁核痛敏单位在激光穴位照射后，有16个单位（33．33％）的痛敏放电被明显抑制，13个单位（27．1％）的痛敏放电受到部分抑制；其余19个单位（39．6%）的痛敏放电在激光照射前后未见明显变化，在4个激光照射有明显抑制效应的单位，注射吗啡受体阻断剂纳络酮后，有3个单位的抑制效应被明显削弱，另外1个单位的抑制效应依然存在。在3个痛敏放电不受激光照射影响的单位，注射吗啡后只有1个单位的痛敏放电受到明显抑制。     

氮激光照射对肿瘤动物的免疫和体外细胞培养效应的观察

激光技术的医学应用在国内外已普遍开展,治疗肿瘤的实验以及激光照射治疗肿瘤后体内免疫过程的变化,已看到了初步的结果。1978年上海海员医院用波长3371埃的     

Accumulation of 125J-triiodothyronine in the transplanted tumors of mice and rats

Investigations carried out in various transplantable tumours (Lewis carcinoma, carcinoma-37, melanoma B-16 in mice and sarcoma-45 in rats) did not show 125J-triiodothyronine accumulation by the tumour.     

大白鼠体内照射治疗白细胞减少症

为了研究砷化镓激光光纤引入机体后对骨髓产生的影响,我们将砷化镓激光光纤直接引入大白鼠体内照射,连续观察了对大白鼠白细胞减少症的治疗作用。现将研究概况介绍如下。 一、材料与方法 1.仪器:使用重庆大学激光光纤科研小组自行装配的XLL型半导体砷化镓激光光纤治疗仪。砷化镓激光以0.5～1.5m长的光纤耦合后插入动物体深部组织。光纤输出端的光功率为1.0～1.3mW,     

Effect of BCG vaccination on the incidence of the development of 90Sr-induced osteosarcomas in rats

The frequency of 90Sr-induced osteosarcoma development was determined in the mongrel rats subjected to BCG vaccination. Injection of BCG (5 mg per animal) is shown to change the frequency of tumour development and their multiplicity only in male rats which were vaccinated 20 days before nuclide administration. An increase up to 10 mg per animal of BCG dose injected 10 days before 90Sr administration caused the carcinogenesis inhibition irrespective of the sex of the animals.     

Effects of heat and electron irradiation on the melting behavior of Al-Si alloy particles and motion of the Al nanosphere within

In situ heating and electron-beam irradiation in the transmission electron microscope were performed to study melting of Al-11.6 at.% Si alloy submicron particles supported on an amorphous-C thin film. It was found that electron irradiation could be used to melt the particles, even when the hot-stage specimen holder was kept at a much lower temperature than the bulk melting point (i.e. the eutectic temperature) of the particles. The critical current densities required to achieve partial melting increased linearly with the incident electron-beam energy for a given temperature. Comparison between this behavior and analytical calculations indicates that melting under electron-beam irradiation is caused by a temperature rise due to electron thermal spikes in the particles and poor thermal conduction away from the particles. The motion of the crystalline Al nanosphere inside the partially molten particles was also investigated, using the electron beam to both stimulate and observe the motion of the nanosphere. The irregular motion observed was quantified as antipersistent fractional Brownian motion. Analysis of possible phenomena contributing to the motion demonstrates that the incident electrons provide the fractional force that moves the Al nanosphere, and that gravity and the oxide shell on the partially molten particle cause the antipersistent behavior. Another interesting phenomenon observed in this study was that the crystalline Al nanosphere inside the partially molten Al-Si alloy particle followed a focused electron beam as it was moved about on the partially molten particle. This observation suggests that it may be possible to manipulate metallic nanospheres inside opaque liquids using an electron beam.     

Effect of gamma irradiation on the low-frequency (1/̷) noise of linear ics: Reliability physics study

Linear integrated circuits IC 709 and 741 were irradiated by gamma rays using cobalt-60 source. Low-frequency noise was measured for these ICs before and after irradiation dose levels 10⁴, 10⁵, 10⁶ and 5 × 10⁶ R. In general IC 741s appeared to be more noisy than IC 709s. The noise levels increase substantially in the case of IC 741 after gamma irradiation of 10⁶ R. Comparative measurement results are presented in this article. These results may be useful to correlate radiation as a defect producing stress, mode and type of failures and reliability of linear ICs.     

The effect of gamma irradiation and forward bias on the 76 K electroluminescence spectrum of GaP:Zn,O

Both the effects of gamma irradiation and high-current forward bias on the low temperature electroluminescence (EL) spectra of GaP:Zn,O light emitting diodes (LEDs) have been studied by measuring constant current (1 mA) 76 K EL spectra below 1000 nm. The LEDs were divided into two sets: a control set which was subjected only to forward bias, and a set exposed to gamma irradiation and forward bias. The EL spectra reveal the growth of sharp, bound exciton emission bands (Z lines) in the range 580 nm to 620 nm following extended high current bias at 300 K of irradiated LEDs and, more weakly, in control LEDs which show pre-bias evidence of these lines. The emergence of these lines is tenatively associated with the recombination-enhanced motion of a defect, possibly the Zn interstitial, which can be introduced by irradiation and is sometimes present in unirradiated LEDs. This article sponsored by the U. S. Department of Energy (DOE) under Contract No. DE-AC04-76-DP00789. A United States Department of Energy Facility.     

Dependence of the annealing kinetics of A centers and divacancies on temperature, particle energy, and irradiation dose for n-Si crystals

n-Si crystals grown by the float-zone method with a phosphorus concentration of ～6×10¹³ cm^?3 and irradiated with 2-MeV electrons and 25-MeV protons were studied. It is shown that the kinetics of the isochronous annealing of the A centers and divacancies (the annealing temperature and the rearrangement of radiation defects in the situation where the dissociation of one type of defects gives rise to more stable defects) depends in a complicated way on the energy, dose, and temperature of irradiation; i.e., this kinetics depends on the relation between the concentrations of various radiation defects and on the charge state of reacting primary radiation defects when they interact with each other, with impurity atoms, and with disordered regions. An increase in the concentration of divacancies in the temperature range of 180–210°C is attributed to the dissociation of disordered regions.